1 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management international, open membership, not- for-profit technology standards consortium. Session 3 Data Modeling ITE 252 Database Management

2 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management Database Design Three-part process: – Conceptual design: Identify requirements of stakeholders and data requirements – Logical design: Identify type of database application needed; data modeling (identifying entities, attributes, relationships) – Physical design: Implementation; physical hardware design and platform; installation and configuration of server and database creation

3 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management Database Design

4 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management international, open membership, not- for-profit technology standards consortium. Database Types 1.Transactional – Supports business transactions For example, sales, Online Transaction Processing (OLTP) – Traditionally a client/server environment – Concerns: Concurrency, throughput

5 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management international, open membership, not- for-profit technology standards consortium. Database Types 2.Decision support system (DSS) – Supports business decisions – Types: Data warehouses, reporting databases, data marts – Primary goal: Data retrieval and evaluation – Bulk loading used to add data – Concerns: Access speeds, throughput 3.Hybrid – Mixture of transactional and DSS types

6 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management international, open membership, not- for-profit technology standards consortium. Modeling Goals Design with understanding that: – All applications written for database are dependent on database structure – If database is altered, applications may need to be altered or rewritten Support business objectives Simple, easy-to-read, easy-to-comprehend structure Scalability

7 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management international, open membership, not- for-profit technology standards consortium. Business Rules Business rules: – Processes and flows used in organization’s daily work, including: Organizational policies Calculations and formulas Rules and regulations Database systems should support business rules – Some rules may be better enforced by database design – Others may be better handled through database application

8 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management international, open membership, not- for-profit technology standards consortium. Entity-Relationship (E-R) Modeling Entities: – “Things” to track in database Physical objects (people or products) Conceptual entities (loan balances or interest rates)

9 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management international, open membership, not- for-profit technology standards consortium. Entity-Relationship (E-R) Modeling Attributes: – Information tracked about entity – Each entity has attributes – For example: Entity: Employees Attributes: Hire Date, Pay Rate, Social Security ID, Employee Number, Home Address – One attribute used as unique identifier or primary key

10 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management Entity-Relationship (E-R) Modeling Relationships: – When one entity references information from another entity – For example: Time Card entity must reference an Employee entity – Time Card entity is referencing entity – Employee entity is referenced entity – Primary keys ensure referential integrity

11 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management Entity-Relationship (E-R) Modeling

12 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management Basic Database Objects Tables: Store unique instances of entity – Columns (fields) represent attributes – Rows (records) represent individual occurrences of that entity Views: – Customized representations of table information

13 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management Basic Database Objects

14 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management Basic Database Objects Index: – Organizes and sorts data – Provides pointer to specific physical location of data on storage media – May be: Primary or secondary Clustered or nonclustered – Balanced-tree index (b-tree, or binary tree index): Most common type of index in modern databases

15 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management B-Tree Index

16 Nassau Community CollegeProf. Vincent Costa Acknowledgements: Introduction to Database Management, All Rights ReservedIntroduction to Database Management international, open membership, not- for-profit technology standards consortium. Homework Read Chapter Two, pp Look Over Chapter Three, pp